SQL中的單記錄函數(shù)盤點(diǎn)
甲骨文將一直致力于保持Java和整個生態(tài)系統(tǒng)的強(qiáng)勁穩(wěn)定。下面是小編收集的關(guān)于SQL中的單記錄函數(shù)盤點(diǎn)，希望大家認(rèn)真閱讀!
1.ASCII
返回與指定的字符對應(yīng)的十進(jìn)制數(shù);
SQL> select ascii('A') A,ascii('a') a,ascii('0') zero,ascii(' ') space from dual;
A A ZERO SPACE
--------- --------- --------- ---------
65 97 48 32
2.CHR
給出整數(shù),返回對應(yīng)的字符;
SQL> select chr(54740) zhao,chr(65) chr65 from dual;
ZH C
-- -
趙 A
3.CONCAT
連接兩個字符串;
SQL> select concat('010-','88888888')||'轉(zhuǎn)23' 高乾競電話 from dual;
高乾競電話
----------------
010-88888888轉(zhuǎn)23
4.INITCAP
返回字符串并將字符串的第一個字母變?yōu)榇髮?
SQL> select initcap('smith') upp from dual;
UPP
-----
Smith
5.INSTR(C1,C2,I,J)
在一個字符串中搜索指定的字符,返回發(fā)現(xiàn)指定的字符的位置;
C1 被搜索的字符串
C2 希望搜索的字符串
I 搜索的開始位置,默認(rèn)為1
J 出現(xiàn)的位置,默認(rèn)為1
SQL> select instr('oracle traning','ra',1,2) instring from dual;
INSTRING
---------
9
6.LENGTH
返回字符串的長度;
SQL> select name,length(name),addr,length(addr),sal,length(to_char(sal)) from gao.nchar_tst;
NAME LENGTH(NAME) ADDR LENGTH(ADDR) SAL LENGTH(TO_CHAR(SAL))
------ ------------ ---------------- ------------ --------- --------------------
高乾競 3 北京市海錠區(qū) 6 9999.99 7
7.LOWER
返回字符串,并將所有的字符小寫
SQL> select lower('AaBbCcDd')AaBbCcDd from dual;
AABBCCDD
--------
aabbccdd
8.UPPER
返回字符串,并將所有的字符大寫
SQL> select upper('AaBbCcDd') upper from dual;
UPPER
--------
AABBCCDD
9.RPAD和LPAD(粘貼字符)
RPAD 在列的右邊粘貼字符
LPAD 在列的左邊粘貼字符
SQL> select lpad(rpad('gao',10,'*'),17,'*')from dual;
LPAD(RPAD('GAO',1
*******gao*******
不夠字符則用*來填滿
10.LTRIM和RTRIM
LTRIM 刪除左邊出現(xiàn)的字符串
RTRIM 刪除右邊出現(xiàn)的字符串
SQL> select ltrim(rtrim(' gao qian jing ',' '),' ') from dual;
LTRIM(RTRIM('
gao qian jing
11.SUBSTR(string,start,count)
取子字符串,從start開始,取count個
SQL> select substr('13088888888',3,8) from dual;
SUBSTR('
08888888
12.REPLACE('string','s1','s2')
string 希望被替換的字符或變量
s1 被替換的字符串
s2 要替換的字符串
SQL> select replace('he love you','he','i') from dual;
REPLACE('H
i love you
13.SOUNDEX
返回一個與給定的字符串讀音相同的字符串
SQL> create table table1(xm varchar(8));
SQL> insert into table1 values('weather');
SQL> insert into table1 values('wether');
SQL> insert into table1 values('gao');
SQL> select xm from table1 where soundex(xm)=soundex('weather');
XM
weather
wether
14.TRIM('s' from 'string')
LEADING 剪掉前面的字符
TRAILING 剪掉后面的字符
如果不指定,默認(rèn)為空格符
15.ABS
返回指定值的絕對值
SQL> select abs(100),abs(-100) from dual;
ABS(100) ABS(-100)
100 100
16.ACOS
給出反余弦的值
SQL> select acos(-1) from dual;
ACOS(-1)
3.1415927
17.ASIN
給出反正弦的值
SQL> select asin(0.5) from dual;
ASIN(0.5)
.52359878
18.ATAN
返回一個數(shù)字的反正切值
SQL> select atan(1) from dual;
ATAN(1)
.78539816
19.CEIL
返回大于或等于給出數(shù)字的最小整數(shù)
SQL> select ceil(3.1415927) from dual;
CEIL(3.1415927)
4
20.COS
返回一個給定數(shù)字的余弦
SQL> select cos(-3.1415927) from dual;
COS(-3.1415927)
-1
21.COSH
返回一個數(shù)字反余弦值
SQL> select cosh(20) from dual;
COSH(20)
242582598
22.EXP
返回一個數(shù)字e的n次方根
SQL> select exp(2),exp(1) from dual;
EXP(2) EXP(1)
7.3890561 2.7182818
23.FLOOR
對給定的數(shù)字取整數(shù)
SQL> select floor(2345.67) from dual;
FLOOR(2345.67)
2345
24.LN
返回一個數(shù)字的對數(shù)值
SQL> select ln(1),ln(2),ln(2.7182818) from dual;
LN(1) LN(2) LN(2.7182818)
0 .69314718 .99999999
25.LOG(n1,n2)
返回一個以n1為底n2的對數(shù)
SQL> select log(2,1),log(2,4) from dual;
LOG(2,1) LOG(2,4)
0 2
26.MOD(n1,n2)
返回一個n1除以n2的余數(shù)
SQL> select mod(10,3),mod(3,3),mod(2,3) from dual;
MOD(10,3) MOD(3,3) MOD(2,3)
1 0 2
27.POWER
返回n1的n2次方根
SQL> select power(2,10),power(3,3) from dual;
POWER(2,10) POWER(3,3)
1024 27
28.ROUND和TRUNC
按照指定的精度進(jìn)行舍入
SQL> select round(55.5),round(-55.4),trunc(55.5),trunc(-55.5) from dual;
ROUND(55.5) ROUND(-55.4) TRUNC(55.5) TRUNC(-55.5)
56 -55 55 -55
29.SIGN
取數(shù)字n的符號,大于0返回1,小于0返回-1,等于0返回0
SQL> select sign(123),sign(-100),sign(0) from dual;
SIGN(123) SIGN(-100) SIGN(0)
1 -1 0
30.SIN
返回一個數(shù)字的正弦值
SQL> select sin(1.57079) from dual;
SIN(1.57079)
1
31.SIGH
返回雙曲正弦的值
SQL> select sin(20),sinh(20) from dual;
SIN(20) SINH(20)
.91294525 242582598
32.SQRT
返回數(shù)字n的根
SQL> select sqrt(64),sqrt(10) from dual;
SQRT(64) SQRT(10)
8 3.1622777
33.TAN
返回數(shù)字的正切值
SQL> select tan(20),tan(10) from dual;
TAN(20) TAN(10)
2.2371609 .64836083
34.TANH
返回數(shù)字n的雙曲正切值
SQL> select tanh(20),tan(20) from dual;
TANH(20) TAN(20)
1 2.2371609
35.TRUNC
按照指定的'精度截取一個數(shù)
SQL> select trunc(124.1666,-2) trunc1,trunc(124.16666,2) from dual;
TRUNC1 TRUNC(124.16666,2)
100 124.16
36.ADD_MONTHS
增加或減去月份
SQL> select to_char(add_months(to_date('199912','yyyymm'),2),'yyyymm') from dual;
TO_CHA
200002
SQL> select to_char(add_months(to_date('199912','yyyymm'),-2),'yyyymm') from dual;
TO_CHA
199910
37.LAST_DAY
返回日期的最后一天
SQL> select to_char(sysdate,'yyyy.mm.dd'),to_char((sysdate)+1,'yyyy.mm.dd') from dual;
TO_CHAR(SY TO_CHAR((S
2004.05.09 2004.05.10
SQL> select last_day(sysdate) from dual;
LAST_DAY(S
31-5月 -04
38.MONTHS_BETWEEN(date2,date1)
給出date2-date1的月份
SQL> select months_between('19-12月-1999','19-3月-1999') mon_between from dual;
MON_BETWEEN
9
SQL>selectmonths_between(to_date('2000.05.20','yyyy.mm.dd'),to_date('2005.05.20','yyyy.mm.dd')) mon_betw from dual;
MON_BETW
-60
39.NEW_TIME(date,'this','that')
給出在this時區(qū)=other時區(qū)的日期和時間
SQL> select to_char(sysdate,'yyyy.mm.dd hh24:mi:ss') bj_time,to_char(new_time
2 (sysdate,'PDT','GMT'),'yyyy.mm.dd hh24:mi:ss') los_angles from dual;
BJ_TIME LOS_ANGLES
2004.05.09 11:05:32 2004.05.09 18:05:32
40.NEXT_DAY(date,'day')
給出日期date和星期x之后計算下一個星期的日期
SQL> select next_day('18-5月-2001','星期五') next_day from dual;
NEXT_DAY
25-5月 -01
41.SYSDATE
用來得到系統(tǒng)的當(dāng)前日期
SQL> select to_char(sysdate,'dd-mm-yyyy day') from dual;
TO_CHAR(SYSDATE,'
09-05-2004 星期日
trunc(date,fmt)按照給出的要求將日期截斷,如果fmt='mi'表示保留分,截斷秒
SQL> select to_char(trunc(sysdate,'hh'),'yyyy.mm.dd hh24:mi:ss') hh,
2 to_char(trunc(sysdate,'mi'),'yyyy.mm.dd hh24:mi:ss') hhmm from dual;
HH HHMM
2004.05.09 11:00:00 2004.05.09 11:17:00
42.CHARTOROWID
將字符數(shù)據(jù)類型轉(zhuǎn)換為ROWID類型
SQL> select rowid,rowidtochar(rowid),ename from scott.emp;
ROWID ROWIDTOCHAR(ROWID) ENAME
AAAAfKAACAAAAEqAAA AAAAfKAACAAAAEqAAA SMITH
AAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLEN
AAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARD
AAAAfKAACAAAAEqAAD AAAAfKAACAAAAEqAAD JONES
43.CONVERT(c,dset,sset)
將源字符串 sset從一個語言字符集轉(zhuǎn)換到另一個目的dset字符集
SQL> select convert('strutz','we8hp','f7dec') "conversion" from dual;
conver
strutz
44.HEXTORAW
將一個十六進(jìn)制構(gòu)成的字符串轉(zhuǎn)換為二進(jìn)制
45.RAWTOHEXT
將一個二進(jìn)制構(gòu)成的字符串轉(zhuǎn)換為十六進(jìn)制
46.ROWIDTOCHAR
將ROWID數(shù)據(jù)類型轉(zhuǎn)換為字符類型
47.TO_CHAR(date,'format')
SQL> select to_char(sysdate,'yyyy/mm/dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
2004/05/09 21:14:41
48.TO_DATE(string,'format')
將字符串轉(zhuǎn)化為ORACLE中的一個日期
49.TO_MULTI_BYTE
將字符串中的單字節(jié)字符轉(zhuǎn)化為多字節(jié)字符
SQL> select to_multi_byte('高') from dual;
TO
高
50.TO_NUMBER
將給出的字符轉(zhuǎn)換為數(shù)字
SQL> select to_number('1999') year from dual;
YEAR
1999